The patent application of John F. Taplin, filed June 23, 1973, Ser. No. 265,637 for PRINTING AND PROCESSING INFORMATION IN BINARY FORM, now U.S. Pat. No. 3,896,917, discloses means for printing information in form of bars of equal height and variable width and inter-bar spaces of variable width wherein each bar and each inter-bar space signifies a bit of information. The patent application of Leland J. Hanchett, filed Sept. 17, 1973 Ser. No. 398,035 for BAR CODE PROCESSING AND DETECTING SYSTEM, now U.S. Pat. No. 3,900,832, discloses in a general way a system for processing bar coded information of the kind disclosed in the above patent application of John P. Taplin. This invention is more particularly concerned with the stage in the above patent application of Leland J. Hanchett intended for error detection and sequence check. This stage precedes the code conversion stage in the system which is disclosed in the above patent application of Leland J. Hanchett.
The most important code to be processed is one wherein each character is made up of four bars of equal height and three inter-bar spaces, and wherein each of the bars may have one of two possible widths, and each of the inter-bar spaces may have one of two possible widths, so that 128 different combinations may be formed of the four bars and the three inter-bar spaces of which each character is constituted.
While the present invention is not limited to error detection and sequence checking of information which is coded in the aforementioned manner, it is particularly useful in connection with processing information which is coded in that way and the processing of information which is coded in this fashion will be considered below with particularity.